Bridge Review: Message Meaning, Topic Evidence, and QoS Compatibility

This route assumes the topic model from ros2-for-students is already understood. It does not reteach publishers, subscribers, ros2 topic list, or message basics from scratch.

The bridge question is:

What extra evidence is required before a Java-side assumption about sensor data can be compared responsibly with a live or supplied ROS 2 message stream?

Keep one /scan path in view and inspect:

• the declared message type;
• the fields the Java-side logic would care about;
• one observed or supplied message instance;
• publisher/subscriber endpoint information;
• QoS compatibility where relevant;
• the distinction between compatible endpoints and successful physical sensing.

The important chain is:

message schema
→ endpoint compatibility
→ observed message evidence
→ application interpretation
→ still-separate physical claim

Required artifact

Produce a ROS Message Compatibility Record containing the interface, selected fields, one message sample, endpoint/QoS evidence, one Java-side expectation, and one claim that remains unsupported.

If topics or QoS fundamentals are unfamiliar, return to ros2-for-students rather than expanding this bridge route.